Frequency control means



March 27, 1934. H. cHlRElx FREQUENCY CONTROL MEANS Filed Aug. 27, 1951 INVENTOR HENRI CHlRElX BY Z Mrz/W ATTORNEY Patented Mar. 27, 1934 1TB STATES FREQUENCY CONTROL MEANS Henri Chireix, Paris, France, assigner to Compagnie Generale de Telegraphie Sans Fil, Paris,

France, a corporation of France Application August 27, 1931, serial No. 559,638

In France August 28, 1930 3 Claims. (Cl. Z50-36) l is constant and lagging in quadrature at resonance frequency, and in bringing out the variations in phase experienced by each one oi the resultants of these two pairs of current as the frequency varies7 and utilizing said variations for l measuring purposes.

The differential potential obtained across the output terminals of two detectors, to the input terminals ci each of which there has been fed a resultant potential obtained as indicated above,

to be regulated as to frequency.

An object of the present application is to disclose, on the one hand, means for accomplishing the broad idea outlined above, and, on the other i" hand, to disclose an arrangement in which the variations produced are used to regulate or control an oscillation generator.

To carry the general idea into practice, I may use a rigid assembly consisting of two coils or loops disposed along the same vertical axis, with their planes arranged .at right angles to each other. One oi said coils cfr-loops is tuned and comprises two taps to which are connected the detectors. When the two loops are moved into the iield oi a source of high frequency venergyY the combined action of the second loop and the frequency source coupled with the second loop will set up in the conductors united with the said taps resultant currents, the nature of which will be described more in detail hereinafter. These currents are used in a differential circuit arrangement whose output current vis employed to control a generator that is to be regulated.

What shall now be described by way of example is an embodiment of an arrangement wlfiereinA the means according to these ideas are utilized. This embodiment is illustrated in the accompanying drawing in which Figure 1 shows the means for producing the controlling energy and the frequency generator controlled thereby; while,

Figure 2 shows diagrammatically the direction in which the currents flow in the wires of the loops and the relation between the phases of the several voltages produced in the loops of Figure l.

may be used for the control of a generator that is The reference numerals 1 and 2 designate two coils or loops constituting a rigid assembly mounted on the same vertical axis, with their planes at right angles to each other. The loops 1 and 2 are coupled as shown with the transmitter 3. 60 A variable condenser 4 is connected across the terminals of the loop 2 thus constituting a tuning circuitl resulting in avery high over-voltage. A variable condenser 5 connected across the terminals of loop 1 serves to control the power absorbed 65 (picked up) by the loop by tuning the loop to a frequency more or less remote with respect to the point at which it will be resonant to the energy picked up. Means for compensating the effect of mutual coupling between the loops 1 and 2 is pro- 70 vided in the form of a movable closed loop Vor spire of wire short-circuited upon itself and disposed in the iield of loops 1 and 2 as shown.

, Loop 2 is connectedbytaps and 'Ito the grids of tubes 8 and 9 which act as detectors. The amount 75 of anode current flowing in these tubes from the anode current source 10 may be read by means of an ammeter 11. Two resistances 12 and 13 of an orderrof magnitude of 50,000 ohms, are included in the anode circuits of the tubes 8 and 9. 80 The resistances 12 and 13 are united at their ends as shown and thus result in a symmetric circuit arrangement.

A direct current amplier 14 has its control electrode to cathode impedance connected to the S5 terminals of resistances 13 and 14 and its anode and cathode circuit supplied from a direct current source 15. The tube 14 amplies the variations ofpotential appearing across the terminals 16 and 17 of the two resistances 12 and 13. The 90 direct current winding of the saturated (ironcored) inductance 18 isconnected in the anode circuit of the amplifier 14. A n ammeter 19 in the direct current anode cathode circuit of 14 indicates the current flowing through said inductance coil. The control electrode of amplifier 14 is negatively biased by the battery 28 so that the anode current of 14 as indicated by 19 will be of the desired mean value in the presence of resonance, when the potential drop between 16 and 17 100 1s zero. Y

The radio frequency winding of the inductance coil 18 is directly united with the antenna inductance 20 of the transmitter 3 by way of a condenser 21 and inductance 33.

Anirneter 11 indicates the sum total of currents i1 and i2 (representative of the currents in loops 1 and 2) passing in the anode circuits of tubes 8 and 9. The indications or readings of ammeter 19 will be proportional to the difference of these 1.21.0

currents i1 and i2. If z'i=2, ammeter 19 will indicate the "rest or normal current, that is, the current resulting from the initial or normal polarization of the grids of amplifier 14.

The circuit scheme is completed by the grounding of the electrodes of the tubes l8, 9 and 14 by way of vcondensers 22, 23, 24 and 25, in orderto preclude the flow of radio frequency currents in the direct current amplifier 14.

The operation of the frequency regulator is as follows:

Assuming that the frequency of the transmitter 3 is correct. The transmitter is coupled with the loops 1 and 2 by way of the coil 29. The tubes 8 and 9 are operative. Tube 14 is inoperative. The taps or terminals 6 and 7 are brought to the middle point 27 of the loop 2. With loop 2 entirely untuned by the aid of condenser 4, condenser 5 is set in such a Way as to obtain a certain current in the ammeter 11, this current being determined lin 'away so as to insure sufficient sensitiveness of theapparatus, when condenser 5 is set to a value such that the loop 1 is tuned to a point at which `rit lis not resonant to the currents induced therein from the generator 3 by way of inductance 29.

Nextfthe closed turn or spire 26 is so positioned 'with respect to '1 and 2 as to eliminate any possible efxisting reaction produced in loop 1 by loop 2. It is possible to ascertain such as follows. If the taps I6 and 7 are moved away from each other `a't either side of the point 27, and there is no change in the reading' of ammeter 11, the

condenser 4, as will be understood, remaining in the same `position as before, in other words, so

that the loop 2 is entirely untuned, then there is lno eiiective mutual coupling between 1 and 2.

The tuning position of the condenser 5 and the coupling position of the turn 26 having been ascertained, the desired position of the taps 6 and 7 should .now be determined. For this purpose, 'the #taps 6 and '7 are moved away from point 27 'upon both lsides of the latter, while the condenser 4is .adjusted to tune the loop to and through the resonance point. With due consideration of the Sensitivity of the arrangement, itis preferable that positions 6 and 7 should be such that the reading of ammeter 11, in the presence of circuit resonance, will be twice that observed when the loop 2'was entirely detuned. It is also desirable that these positions should be synunetric with referencefto point 27. However, both these demands or conditions are not absolutely indispensable. 1In practice the arrangement is operable, though with less sensitiveness, even when the said stipulations are not fulfilled.

After the condenser 4 has been. set in a position at which its circuit is resonant to the generated frequency, as indicated above, the tube 14 may be put in operation. Current flowing in tube 14 will cause a deflection Aof Athe indicator or hand of ammeter 19. This reading will 'be due solely to the value of the bias applied bythe battery 28 Ibetween the input electrodes of 14 when taps 6 `and 7 `are:symmetrically spaced from 27. When the potentials at points 16 and 17, due to 'the anode current in 8 and 9, are the same, zero ypotential is applied to the input electrodes of 14. Incase the taps `6 and 7 are unsymmetrical, that is, unequally 'spaced with respect to 27, the vpotential applied between the input electrodes of 14 will vary :slightly with respect to zero value.

In order to use this differential eifect it is now necessary to set the coupling between the regulator and a part of the oscillation circuit of the transmitter 3 to such a value that the current read in the ammeter 19 Will remain unaltered as long as the wave length produced by the generator remains constant, and so that whenever a change in the length of the wave generated in 3 occurs the current flowing in 19 changes. This change in current will act through 18, 21, etc., upon element 20 and the frequency determining character thereof will undergo a change in a sense tending to-correct the variation in frequency that has caused the change.

rlhe `regulator will now function automatically. A change in the frequency of the transmitter 3 results in detuning of the loop 2 which in turn results in 'a variation in the phases of the currents flo-wing in 6 and 7. After detection of these currents there is obtained a potential drop be- 'tween 1'6 :and 17 which differs from the one prevailing at perfect resonance.

This drop is no longer of Zero value if the positions vof the taps 6 vand 7 are maintained symmetric. This variation in potential produces a corresponding variation of the current in the ammeter 19 and in the inductance lwhich affects tha coupling with the element 20 and the value of the latter. This results lin correcting the initial detuning of the transmitter as has been pointed out before.

The invention, as will be understood, is susceptible of a great number of modifications obvious to a man trained in the art, particularly in so far as the number of tubes in parallel or in cascade of the amplifier is concerned, and further in the mode of using the dierential action to control the circuit of the transmitter, generator, etc. X

What I claim is:

1. Means for regulating the frequency of a sourcey of alternating current including, two closed circuits coupled with said source of alternating current, means to eliminate mutual inductance between said closed circuits, means for tuning one of said closed circuits to the frequency of the current from said source, said other circuit being detuned, a connection between said circuits, a pair of therinionic tubes in push-pull arrangement, means comprising a movable tap at each side of said connection between said circuits for connecting one of said circuits to the input elements of said tubes, a work circuit connected to the output elements of said tubes, a coupling between said work circuit and said frequency source,

and means .in said coupling and in said source HENRI CHIREIX. 

